The long-term goal of this project is to identify tumor susceptibility genes involved in lung cancer development. There are six specific aims: 1) to generate pedigrees for lung cancer susceptible families; 2) to obtain normal and tumor tissue samples from as many family members as possible; 3) to genotype DNA from family members with appropriate markers; 4) to perform linkage analyses to identify potential loci involved in lung cancer susceptibility; 5) to genotype the entire genome with equally spaced microsatellite markers and perform linkage analysis with these data; and, 6.) if putative loci are localized, to refine the linkage map of the candidate loci.